Abstract: Greenhouse experiments were conducted to determine the effects of straw, CaCO3, and MnO2 on the electrochemical and chemical kinetics and rice growth and yield in a flooded acid sulfate soil.Straw (0. 25% by weigh of the dry soil) application had a pronounced effect on soil reduction. High concentration of watersoluble Fe2+ stunted plants at early growth (but the Fe2+ concentration gradually decreased and plants had vig-orus growth at maturity. Grain and straw yields at harvest were higher. Potassium in the plant tissue was hight where straw was added.Adding CaCO2(0. 25% by weight of the dry soil) markedly increased soil soltuation pH,decreased Eh and EC,and significantly depressd concentrations of water-soluble Fe2+ ,Mn2+ and Al3+.Calcium carbonate,alone or in combination with MnO2,depressed Fe concentration in the soil solution and signficantly increased straw and grain yields. Calcium and MnOj applications also enhanced N and P content in the straw but decreased Zn content.Adding 0. 005% MnO2(by weight of the dry soil) increased the Mn in the soil solution,depressd the Fe:Mn ratio in the plant tissue,and increased grain yield significantly over the control. Results show that straw as an inexpensive amendment for acid sulfate soils merits further study.